#include<stdio.h>
#include<unistd.h>
#include<sys/types.h>
int main(){

    while(1){
        pid_t id = getpid();
        pid_t fid = getppid();
        printf("hello world! \t pid : %d; ppid : %d\n",id,fid);
        sleep(1);
    }
    return 0;
}
